accretion disk

noun

variants or less commonly accretion disc

plural accretion disks also accretion discs

: a disk of usually gaseous matter surrounding a massive celestial object (such as a black hole) in which the matter gradually spirals in toward and accretes onto the object as a result of gravitational attraction

Evans' team studied a supermassive black hole with jets 800 million light-years away named 3C 33. They never found an expected X-ray pattern … which results from light reflecting off the accretion disk.

—Bill Andrews

Most other moons are either captured planetesimals, or they formed along with the planet in a common accretion disc.

—Daniel Herwartz, et al.

Examples of accretion disk in a Sentence

Recent Examples on the Web

That idea arose largely because earlier telescopes lacked the resolution needed to separate light from the accretion disk, the dusty torus and outflows, blending all of these structures into a single unresolved glow, according to the NASA statement. —Sharmila Kuthunur, Space.com, 19 Jan. 2026

These nuclei pump heat, dust, and gas into their environments, some circling in bright accretion disks, while some escape far beyond the galaxy’s edges. —Neetika Walter, Interesting Engineering, 1 Oct. 2025

This captive matter will form a flattened disk called an accretion disk. —Phil Plait, Scientific American, 4 Sep. 2025

At the limit of the black hole is its accretion disk—that bright orange-yellow swirl of superheated material that the black hole has pulled to its vicinity. —Isaac Schultz / Gizmodo, Quartz, 7 May 2024

Word History

First Known Use

1972, in the meaning defined above

Rhymes for accretion disk

• videodisc
• basilisk
• bisque
• brisk
• disc
• fisc
• fisk
• frisk
• risk
• whisk